Protesters are being accused of hypocrisy, as some ask why they didn't turn out for the Black Lives Matter movement, which was set up in 2013 to end police violence against black people and highlight the impact of gun violence in ethnic minority communities.

Debate on Twitter focused on a photograph of white protesters holding up their palms, which read: "Don't shoot." The slogan and gesture became a rallying cry in 2014 after 18-year-old Michael Brown, who was reported to be raising his arms, was fatally shot by a white police officer in Ferguson, Missouri.

Accusations that the weekend marches had appropriated the slogan were shared more than 3,000 times.

I suspect that what black people really want is some extension of intellectual property rights law so that every time a white person says a black catchphrase, or dances a black step, or wears his pants baggy or whatever, he has to pay a nickel into a fund that will be shared out among all black people.